Re: [PATCH 05.1/16] of:overlay: missing name, phandle, linux,phandle in new nodes

[Alan Tull]

On Wed, Oct 10, 2018 at 1:49 AM Frank Rowand <frowand.list@xxxxxxxxx> wrote:
>
> On 10/09/18 23:04, frowand.list@xxxxxxxxx wrote:
> > From: Frank Rowand <frank.rowand@xxxxxxxx>
> >
> >
> > "of: overlay: use prop add changeset entry for property in new nodes"
> > fixed a problem where an 'update property' changeset entry was
> > created for properties contained in nodes added by a changeset.
> > The fix was to use an 'add property' changeset entry.
> >
> > This exposed more bugs in the apply overlay code.  The properties
> > 'name', 'phandle', and 'linux,phandle' were filtered out by
> > add_changeset_property() as special properties.  Change the filter
> > to be only for existing nodes, not newly added nodes.
> >
> > The second bug is that the 'name' property does not exist in the
> > newest FDT version, and has to be constructed from the node's
> > full_name.  Construct an 'add property' changeset entry for
> > newly added nodes.
> >
> > Signed-off-by: Frank Rowand <frank.rowand@xxxxxxxx>
> > ---
> >
> >
> > Hi Alan,
> >
> > Thanks for reporting the problem with missing node names.
> >
> > I was able to replicate the problem, and have created this preliminary
> > version of a patch to fix the problem.
> >
> > I have not extensively reviewed the patch yet, but would appreciate
> > if you can confirm this fixes your problem.
> >
> > I created this patch as patch 17 of the series, but have also
> > applied it as patch 05.1, immediately after patch 05/16, and
> > built the kernel, booted, and verified name and phandle for
> > one of the nodes in a unittest overlay for both cases.  So
> > minimal testing so far on my part.
> >
> > I have not verified whether the series builds and boots after
> > each of patches 06..16 if this patch is applied as patch 05.1.
> >
> > There is definitely more work needed for me to complete this
> > patch because it allocates some more memory, but does not yet
> > free it when the overlay is released.
> >
> > -Frank
> >
> >
> >  drivers/of/overlay.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++++----
> >  1 file changed, 67 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
> > index 0b0904f44bc7..9746cea2aa91 100644
> > --- a/drivers/of/overlay.c
> > +++ b/drivers/of/overlay.c
> > @@ -301,10 +301,11 @@ static int add_changeset_property(struct overlay_changeset *ovcs,
> >       struct property *new_prop = NULL, *prop;
> >       int ret = 0;
> >
> > -     if (!of_prop_cmp(overlay_prop->name, "name") ||
> > -         !of_prop_cmp(overlay_prop->name, "phandle") ||
> > -         !of_prop_cmp(overlay_prop->name, "linux,phandle"))
> > -             return 0;
> > +     if (target->in_livetree)
> > +             if (!of_prop_cmp(overlay_prop->name, "name") ||
> > +                 !of_prop_cmp(overlay_prop->name, "phandle") ||
> > +                 !of_prop_cmp(overlay_prop->name, "linux,phandle"))
> > +                     return 0;
>
> This is a big hammer patch.
>
> Nobody should waste time reviewing this patch.

I wasn't clear if you still could use the testing so I did re-run my
test.  This patch adds back some of the missing properties, but the
the kobject names aren't set as dev_name() returns NULL:

* without this patch some of_node properties don't show up in sysfs:
root@arria10:~# ls
/sys/bus/platform/drivers/altera_freeze_br/ff200450.\<NULL\>/of_node
clocks            compatible        interrupt-parent  interrupts        reg

* with this patch, the of_node properties phandle and name are back:
root@arria10:~#  ls
/sys/bus/platform/drivers/altera_freeze_br/ff200450.\<NULL\>/of_node
clocks            compatible        interrupt-parent  interrupts
 name              phandle           reg

root@arria10:~# cat
/sys/bus/platform/drivers/altera_freeze_br/ff200450.\<NULL\>/of_node/name
freeze_controllerroot@arria10:~#  ("freeze_controller" w/o the \n so
the name is correct)

* with or without the patch I see the behavior I reported yesterday,
kobj names are NULL.
root@arria10:~# ls /sys/bus/platform/drivers/altera_freeze_br/
bind             ff200450.<NULL>  uevent           unbind

root@arria10:~# ls /sys/bus/platform/drivers/altera_gpio/
bind             ff200010.<NULL>  ff200020.<NULL>  ff200030.<NULL>
uevent           unbind

Alan

Alan

>
> The following part should not be needed (though the above section might have
> to become _slightly_ more complex).
>
> -Frank
> >
> >       if (target->in_livetree)
> >               prop = of_find_property(target->np, overlay_prop->name, NULL);
> > @@ -443,10 +444,13 @@ static int build_changeset_next_level(struct overlay_changeset *ovcs,
> >               struct target *target, const struct device_node *overlay_node)
> >  {
> >       struct device_node *child;
> > -     struct property *prop;
> > +     struct property *prop, *name_prop;
> > +     bool has_name = false;
> >       int ret;
> >
> >       for_each_property_of_node(overlay_node, prop) {
> > +             if (!strcmp(prop->name, "name"))
> > +                     has_name = true;
> >               ret = add_changeset_property(ovcs, target, prop, 0);
> >               if (ret) {
> >                       pr_debug("Failed to apply prop @%pOF/%s, err=%d\n",
> > @@ -455,6 +459,57 @@ static int build_changeset_next_level(struct overlay_changeset *ovcs,
> >               }
> >       }
> >
> > +     /*
> > +      * With FDT version 0x10 we may not have the name property,
> > +      * recreate it here from the unit name if absent
> > +      */
> > +
> > +     if (!has_name) {
> > +             const char *p = target->np->full_name, *ps = p, *pa = NULL;
> > +             int len;
> > +
> > +             /*
> > +              * zzz
> > +              * TODO: stash name_prop on a list in ovcs, to be freed
> > +              * after overlay removed
> > +              */
> > +
> > +             while (*p) {
> > +                     if ((*p) == '@')
> > +                             pa = p;
> > +                     else if ((*p) == '/')
> > +                             ps = p + 1;
> > +                     p++;
> > +             }
> > +
> > +             if (pa < ps)
> > +                     pa = p;
> > +             len = (pa - ps) + 1;
> > +
> > +             name_prop = kmalloc(sizeof(*name_prop), GFP_KERNEL);
> > +             if (!name_prop)
> > +                     return -ENOMEM;
> > +
> > +             name_prop->name = kstrdup("name", GFP_KERNEL);
> > +             name_prop->value = kmalloc(len, GFP_KERNEL);
> > +             if (!name_prop->name || !name_prop->value) {
> > +                     ret = -ENOMEM;
> > +                     goto err_free_name_prop;
> > +             }
> > +
> > +             memcpy(name_prop->value, ps, len - 1);
> > +             ((char *)name_prop->value)[len - 1] = 0;
> > +
> > +             name_prop->length = strlen(name_prop->value) + 1;
> > +
> > +             ret = add_changeset_property(ovcs, target, name_prop, 0);
> > +             if (ret) {
> > +                     pr_debug("Failed to apply name_prop @%pOF/%s, err=%d\n",
> > +                              target->np, name_prop->name, ret);
> > +                     goto err_free_name_prop;
> > +             }
> > +     }
> > +
> >       for_each_child_of_node(overlay_node, child) {
> >               ret = add_changeset_node(ovcs, target, child);
> >               if (ret) {
> > @@ -466,6 +521,13 @@ static int build_changeset_next_level(struct overlay_changeset *ovcs,
> >       }
> >
> >       return 0;
> > +
> > +err_free_name_prop:
> > +     kfree(name_prop->name);
> > +     kfree(name_prop->value);
> > +     kfree(name_prop);
> > +     return ret;
> > +
> >  }
> >
> >  /*
> >
>